Page 23 - Focus PT3 2020 Science ( BI Version )

Science PT3 Answers
4. Unicellular organisms are organisms
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that consist of only one cell while HOTS Challenge 2 HOTS Challenge
multicellular organisms are organisms
that consist of more than one cell. Reptiles and amphibians are found less Yellowish and concentrated urine is a sign of
in the Arctic because of the extreme cold dehydration. Be sure to drink enough water to
HOTS Challenge 2 temperatures in the Arctic. Reptiles and maintain very light-coloured urine.
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amphibians are unable to maintain their body
temperature. The body temperature of reptiles
The number of white blood cells produced will and amphibians will change according to the PT3 Practice 3
Form
Form
1 increase to fight or destroy the pathogen that external environment. When the temperature SECTION A
enters our body.
is too low, their body temperature will also
decrease. This will affect their body function 1. A 2. C 3. D
Formative Practice2.2 and can lead to death. Therefore, reptiles and SECTION B
amphibians are difficult to survive in the Arctic.
1. (a) (i) Stoma
1. The food (glucose) made by the plants (ii) Guard cells
is kept in the form of starch. Therefore, Daily Application (b) (i) guard cells
one of the ways to test if photosynthesis Emergency treatments that can be done if a (ii) increase
has occurred is to test for the presence friend is attacked by a heatstroke:
of starch. • Fan the friend while wetting his or her SECTION C
2. (a) X: Photosynthesis skin with water. 1. (a) (i) Homeostasis
Y: Cellular respiration • Apply ice packs on the friend’s armpits, (ii) While jogging, more oxygen is
(b) X: To make food / glucose groin, neck, and back. needed for cellular respiration.
Y: To produce energy • Provide cool drinks or isotonic drinks to Therefore, the heart need to
(c) Process Y the friend. pump more blood to cells in
• Loosen the friend's clothing. the body. Thus, the rate of
Heatstroke prevention: heartbeat will increase.
PT3 Practice 2 • • Drink more water. (b) Cause: The plant lost a lot of
Wear lightweight, light-coloured, loose-
water.
SECTION A fitting clothing, and a wide-brimmed hat if Adaptation: The stoma pores on
must do outdoor activities on a hot day.
1. C 2. A 3. A the leaves are closed to reduce
additional water loss from the leaf
Formative Practice 3.1
to the environment.
SECTION B (c) (i) Kidney
1. We do not sweat a lot on a rainy day.
1. (a) (i) Plant cell Therefore, the excess water in the body (ii) Less than 58 ml/h. The body
(ii) Animal cell loses a lot of water through
(b) (i) used will be removed from the body through sweat.
urine.
(ii) absorbed
2. When our body temperature drops, the Chapter
SECTION C heat production will increase and heat 4 Reproduction
loss will decrease through these actions:
1. (a) Carbon dioxide + Water → Glucose • Blood vessels constrict.
+ Oxygen • Sweat less.
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(b) Cellular respiration process • Hairs stand erect. HOTS Challenge
(c) • Can keep the balance • Skeletal muscles will contract and
of oxygen content in the relax actively. Tiger: Internal fertilisation
atmosphere. • Hormones will be secreted to Toad: External fertilisation
• To support organism's life. increase the body metabolism. External fertilisation is less efficient because:
(d) Photosynthesis process cannot be 3. Dogs cannot remove much heat • A large number of gametes are
carried out without plants. When released into the water and wasted.
plants are depleted, the process through sweating, so they always stick • Gametes live for only a short time, and
of photosynthesis also decreases, out their tongue which allows saliva to many are lost in the water.
resulting in lack of oxygen supply evaporate from the tongue to reduce
the body temperature. • Offspring are often eaten by predators
4. • Transpiration is the process of and reduces the chances of surviving
Chapter losing water from the surface of into adulthood.
3 Coordination and Response plant leaves in the form of water
vapour to the atmosphere through Formative Practice4.1
stomata.
HOTS Challenge 1 • Transpiration helps plants to absorb 1. (a) Sexual reproduction is the
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and transport water and minerals production of offspring through the
from the soil to all parts of the fusion of a male gamete and a
Skin is the organ that plays an important role plants to replace the water lost to female gamete, whereas asexual
in regulating body temperature. Skin injuries the surrounding through the leaves. reproduction is the production
will affect the function of skin to sweat Transpiration also helps in cooling of offspring from a single parent
when the surrounding is hot. This will affect down the plants when water gets without involving any gametes.
the homeostasis of Sally's body because evaporated on a hot day. This (b) Internal fertilisation occurs inside
she cannot regulate her body temperature means transpiration helps plants the body of the female parent
well. Therefore, Sally can only stay in an to regulate water content and after the male parent deposits his
environment where the temperature can be maintain the water content to be in sperms into the female’s body,
maintained at a constant temperature. a balanced and stable condition. whereas external fertilisation
occurs outside the body of the
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00 Answer Fok Science PT3.indd 532 11/19/19 11:31 AM